1. Field of the Invention
The present invention relates to a sensor chip with at least one sensing axis, a detection device provided with the sensor chip, and a method of manufacturing the detection device.
2. Description of the Related Art
Besides the GPS (Global Posting System), the use of such detection device as the magnetic direction detector for providing the azimuth information with excellent sensitivity for the terminal device such as the mobile phone and the on-board car navigation device has been the recent trend.
A generally employed magnetic direction detector is provided with an X-axis magnetic sensor for detecting an X-axis geomagnetism, a Y-axis magnetic sensor for detecting a Y-axis geomagnetism, and a Z-axis magnetic sensor for detecting a Z-axis geomagnetism so as to allow detection of each geomagnetism at three axes, that is, X, Y and Z axes.
The magnetic direction detector has three magnetic sensors and a sensor controlling semiconductor mounted on a surface of a circuit substrate. The respective magnetic sensors and the sensor controlling semiconductor are integrated by sealing with a sealing member formed of such material as an insulating resin (see Japanese Unexamined Patent Application Publication No. 2005-233630).
Each magnetic sensor includes a sensing axis for detecting the geomagnetism. Among those magnetic sensors, the X-axis magnetic sensor is mounted on a main circuit substrate by directing the sensing axis at the angle to detect the geomagnetism in any one of a front-to-rear direction and a left-to-right direction of the magnetic direction detector. The Y-axis magnetic sensor is mounted on the main circuit substrate by directing the sensing axis at the angle to detect the geomagnetism in the other of the front-to-rear direction and the left-to-right direction. The Z-axis magnetic sensor is mounted on a sub-circuit substrate. The sub-circuit substrate with the Z-axis magnetic sensor is designed to stand on the main circuit substrate. The Z-axis magnetic sensor is mounted on the main circuit substrate by directing the sensing axis at the angle to detect the geomagnetism in an up-and-down direction of the magnetic direction detector via the sub-circuit substrate.
Electrodes for conductively connecting the respective magnetic sensors to the sensor controlling semiconductor are formed at each circumferential edge of one surface of the magnetic sensor with a rectangular box shape, and at each circumferential edge of one surface of the sensor controlling semiconductors. Each of the respective electrodes is conductively connected to the electrode of the sensor controlling semiconductor via the lead wire, respectively.
Those X-axis, Y-axis and Z-axis magnetic sensors are manufactured from different wafers exclusively for the respective sensors. That is, each of the resultant magnetic sensors mounted on the magnetic direction detector is fabricated from the different wafer.
The generally employed magnetic direction detector provided with the respective magnetic sensors each formed of the different wafer may vary the magnetic property among the magnetic sensors. Upon detection of the geomagnetism by the aforementioned magnetic direction detector, an error in the detection sensitivity with respect to the geomagnetism detected by the respective magnetic sensors may be observed. As a result, the aforementioned magnetic direction detector may have a risk of failing to detect the accurate geomagnetism.
In the generally employed magnetic direction detector, the Z-axis magnetic sensor is mounted on the main circuit substrate via the sub-circuit substrate. So there may be an error in the detection sensitivity with respect to the geomagnetism between the Z-axis magnetic sensor and the other magnetic sensors. Accordingly, the aforementioned magnetic direction detector may fail to accurately detect the geomagnetism. As the sub-circuit substrate stands on the main circuit substrate, the thickness of the magnetic direction detector may be increased depending on the size of the sub-circuit substrate. The resultant structure fails to satisfy the down-sizing requirement of the magnetic direction detector.